Is the quality of our air getting any better? To help answer that question, scientists examined ten years of observations from the Ozone Monitoring Instrument aboard NASA's Aura satellite. One of the atmospheric gases it detects is nitrogen dioxide (NO2), a yellow-brown gas that is a common emission from cars, power plants and industrial activity. Nitrogen dioxide levels in the atmosphere are used as a general indicator of air quality as the gas can quickly transform into ground-level ozone, a major respiratory pollutant in urban smog. By creating high-resolution maps that show how much nitrogen dioxide concentrations went up or down for each year between 2005 and 2014, scientists were able to track evolving trends in air pollution across the world over the last decade. Watch the video to learn more.